Portable terminals which are used for navigation are commonly known and used.
Terminals of this type are able to determine the location of the user during navigation, and calculate routes in a latitude and longitude matrix from the measured position of a location to the destination, and display the routing information. The measuring methods used in this case are, for instance, the ones which use PHS (Personal Handyphone System: registered trademark) or GPS (Global Positioning System).
When a PHS is used, for instance, measuring is carried out as follows.
A PHS terminal which the user carries, receives annunciation signals transmitted from a plurality of base stations within the PHS network and specifies 2 or 3 annunciation signals in descending order of strength by measuring their electric field strengths. The annunciation signal contains identification information about the base station that is transmitting the signal. The PHS terminal identifies the base station by referring to this identification information. At this point, the location of each base station is already known; thus, the distance between the location of the PHS terminal and the destination base station can be calculated. The navigation path is drawn on the basis of the identification information contained in the annunciation signals transmitted from the base stations.
Incidentally, the navigable areal scope within a PHS network is defined by the radio cells formed by base stations deployed in the PHS network. The radio cell is generally called a micro cell, and its cell domain is relatively small. The size of this cell domain is indeed some hundred meters in diameter.
Therefore, if the location of a PHS terminal is measured by the above measuring method, a positioning error in the range of 100 to 500 meters usually results. There is a fear that the precise navigation path cannot be determined when the destination is calculated, using the measuring method.
The present invention takes into consideration the limitations of the above mentioned prior art, and its object is to provide a measuring device by which the error of the measured outcome can easily be corrected. Thus the invention provides a method for correcting the outcome of the measurement, an apparatus for performing the method, a program and recording media.